My entire original "profit is theft" argument rests on the same kind of assumptions as your "taxes are theft" argument. Namely that in both cases the affected party is not getting anything for their contributions and could have done it themselves. In my mind the only difference here is that taxes are explicit and transparent, while "capturing excess productivity" is hidden. The former seems much more honest in this regard.

Edit:

> You also have no word on where your money goes or any control over it. The people who manage it do not pay penalties for mismanaging it. In private companies I can assure you this is much more sensitive and you are much more careful with what you do than in public instances.

This is patently false. Not only do you have less control over how your employer spends your excess value than how your government spends your taxes (I don't recall being able to vote for my CEO), but corruption in companies is not uncommon. It's just less visible because companies are allowed much more secrecy than governments. This is not any better. It's also rare for a CEO to be seriously punished for running a company into the ground. "Failing upwards" is common.